Vol. 19 No. 17 · 4 September 1997
pages 22-23 | 3075 words
Why Rhino-Mounted Bantu Never Sacked Rome
Armand Marie Leroi
- Guns, Germs and Steel by Jared Diamond
Cape, 480 pp, £18.99, April 1997, ISBN 0 224 03809 5
- Why is Sex Fun? The Evolution of Human Sexuality by Jared Diamond
Weidenfeld, 176 pp, £11.99, July 1997, ISBN 0 297 81775 2
The Martiniquan poet and ideologue of négritude, Aimé Césaire, celebrated the sons and daughters of Africa as
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Letters
Vol. 19 No. 18 · 18 September 1997
From Adrian Bowyer
Armand Marie Leroi’s review of Jared Diamond’s Guns, Germs and Steel (LRB, 4 September) was a welcome reminder that both history and culture are inextricably enracinated in biology. But when Diamond asks, in Leroi’s paraphrase, why ‘a handful of small European nations engaged and conquered the world’, there may not be a causal answer in the scientific sense.
Consider the mathematical thought experiment named after George Polya. Place both a black marble and a white marble in an urn. Now close your eyes, reach in, and take out one marble. Then put it back, together with one more of the same colour. If you keep doing this for a while you might reasonably ask whatwill be the expected ratio of black to white marbles as their numbers grow. The answer is that all proportions are equally probable. Further, if you plot a graph of the count of white marbles against black as their numbers increase it quickly settles down to a straight line, the gradient of which is the random proportion just mentioned – the line is equally likely to point in any direction, but, once established, it continues straight. Any empiricist seeing such a straight line and not knowing its source would assume that its gradient represented the workings of some physical law and had a value pertinent to that law.
There are many things in the world that may come about in the same way: for example, the number of IBM pcs v. Apple Macs, or the number of right-handed as opposed to left-handed people, or the relative wealth (material, cultural or military) of Europe and Africa. It may make no sense to ask why the proportions are what they are: they could just be a consequence of the Polya urn’s message that unto every one that hath shall be given.
Adrian Bowyer
University of Bath
